Task added for IKEv1 NAT detection.

There is already support for both Main and Aggressive Mode.

src/libcharon/sa/tasks/ike_natd_v1.c

@@ -0,0 +1,440 @@
+/*
+ * Copyright (C) 2006-2011 Tobias Brunner,
+ * Copyright (C) 2006-2007 Martin Willi
+ * Copyright (C) 2006 Daniel Roethlisberger
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "ike_natd_v1.h"
+
+#include <string.h>
+
+#include <hydra.h>
+#include <daemon.h>
+#include <sa/keymat_v1.h>
+#include <config/peer_cfg.h>
+#include <crypto/hashers/hasher.h>
+#include <encoding/payloads/hash_payload.h>
+
+typedef struct private_ike_natd_v1_t private_ike_natd_v1_t;
+
+/**
+ * Private members of a ike_natt_t task.
+ */
+struct private_ike_natd_v1_t {
+
+	/**
+	 * Public interface.
+	 */
+	ike_natd_v1_t public;
+
+	/**
+	 * Assigned IKE_SA.
+	 */
+	ike_sa_t *ike_sa;
+
+	/**
+	 * Are we the initiator?
+	 */
+	bool initiator;
+
+	/**
+	 * Keymat derivation (from SA)
+	 */
+	keymat_v1_t *keymat;
+
+	/**
+	 * Did we process any NAT detection payloads for a source address?
+	 */
+	bool src_seen;
+
+	/**
+	 * Did we process any NAT detection payloads for a destination address?
+	 */
+	bool dst_seen;
+
+	/**
+	 * Have we found a matching source address NAT hash?
+	 */
+	bool src_matched;
+
+	/**
+	 * Have we found a matching destination address NAT hash?
+	 */
+	bool dst_matched;
+};
+
+/**
+ * Build NAT detection hash for a host.
+ */
+static chunk_t generate_natd_hash(private_ike_natd_v1_t *this,
+								  ike_sa_id_t *ike_sa_id, host_t *host)
+{
+	hasher_t *hasher;
+	chunk_t natd_chunk, natd_hash;
+	u_int64_t spi_i, spi_r;
+	u_int16_t port;
+
+	hasher = this->keymat->get_hasher(this->keymat);
+	if (!hasher)
+	{
+		DBG1(DBG_IKE, "no hasher available to build NAT-D payload");
+		return chunk_empty;
+	}
+
+	spi_i = ike_sa_id->get_initiator_spi(ike_sa_id);
+	spi_r = ike_sa_id->get_responder_spi(ike_sa_id);
+	port = htons(host->get_port(host));
+
+	/*  natd_hash = HASH(CKY-I | CKY-R | IP | Port) */
+	natd_chunk = chunk_cata("cccc", chunk_from_thing(spi_i),
+						    chunk_from_thing(spi_r), host->get_address(host),
+						    chunk_from_thing(port));
+	hasher->allocate_hash(hasher, natd_chunk, &natd_hash);
+	DBG3(DBG_IKE, "natd_chunk %B", &natd_chunk);
+	DBG3(DBG_IKE, "natd_hash %B", &natd_hash);
+
+	return natd_hash;
+}
+
+/**
+ * Build a faked NAT-D payload to enforce UDP encapsulation.
+ */
+static chunk_t generate_natd_hash_faked(private_ike_natd_v1_t *this)
+{
+	hasher_t *hasher;
+	chunk_t chunk;
+	rng_t *rng;
+
+	hasher = this->keymat->get_hasher(this->keymat);
+	if (!hasher)
+	{
+		DBG1(DBG_IKE, "no hasher available to build NAT-D payload");
+		return chunk_empty;
+	}
+	rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
+	if (!rng)
+	{
+		DBG1(DBG_IKE, "unable to get random bytes for NAT-D fake");
+		return chunk_empty;
+	}
+	rng->allocate_bytes(rng, hasher->get_hash_size(hasher), &chunk);
+	rng->destroy(rng);
+	return chunk;
+}
+
+/**
+ * Build a NAT-D payload.
+ */
+static hash_payload_t *build_natd_payload(private_ike_natd_v1_t *this, bool src,
+										  host_t *host)
+{
+	hash_payload_t *payload;
+	ike_cfg_t *config;
+	chunk_t hash;
+
+	config = this->ike_sa->get_ike_cfg(this->ike_sa);
+	if (src && config->force_encap(config))
+	{
+		hash = generate_natd_hash_faked(this);
+	}
+	else
+	{
+		ike_sa_id_t *ike_sa_id = this->ike_sa->get_id(this->ike_sa);
+		hash = generate_natd_hash(this, ike_sa_id, host);
+	}
+	payload = hash_payload_create(NAT_D_V1);
+	payload->set_hash(payload, hash);
+	chunk_free(&hash);
+	return payload;
+}
+
+/**
+ * Add NAT-D payloads to the message.
+ */
+static void add_natd_payloads(private_ike_natd_v1_t *this, message_t *message)
+{
+	hash_payload_t *payload;
+	host_t *host;
+
+	/* destination has to be added first */
+	host = message->get_destination(message);
+	payload = build_natd_payload(this, FALSE, host);
+	message->add_payload(message, (payload_t*)payload);
+
+	/* source is added second, compared with IKEv2 we always know the source,
+	 * as these payloads are added in the second Phase 1 exchange or the
+	 * response to the first */
+	host = message->get_source(message);
+	payload = build_natd_payload(this, TRUE, host);
+	message->add_payload(message, (payload_t*)payload);
+}
+
+/**
+ * Read NAT-D payloads from message and evaluate them.
+ */
+static void process_payloads(private_ike_natd_v1_t *this, message_t *message)
+{
+	enumerator_t *enumerator;
+	payload_t *payload;
+	hash_payload_t *hash_payload;
+	chunk_t hash, src_hash, dst_hash;
+	ike_sa_id_t *ike_sa_id;
+	host_t *me, *other;
+	ike_cfg_t *config;
+
+	/* precompute hashes for incoming NAT-D comparison */
+	ike_sa_id = message->get_ike_sa_id(message);
+	me = message->get_destination(message);
+	other = message->get_source(message);
+	dst_hash = generate_natd_hash(this, ike_sa_id, me);
+	src_hash = generate_natd_hash(this, ike_sa_id, other);
+
+	DBG3(DBG_IKE, "precalculated src_hash %B", &src_hash);
+	DBG3(DBG_IKE, "precalculated dst_hash %B", &dst_hash);
+
+	enumerator = message->create_payload_enumerator(message);
+	while (enumerator->enumerate(enumerator, &payload))
+	{
+		if (payload->get_type(payload) != NAT_D_V1)
+		{
+			continue;
+		}
+		hash_payload = (hash_payload_t*)payload;
+		if (!this->dst_seen)
+		{	/* the first NAT-D payload contains the destination hash */
+			this->dst_seen = TRUE;
+			hash = hash_payload->get_hash(hash_payload);
+			DBG3(DBG_IKE, "received dst_hash %B", &hash);
+			if (chunk_equals(hash, dst_hash))
+			{
+				this->dst_matched = TRUE;
+			}
+			continue;
+		}
+		/* the other NAT-D payloads contain source hashes */
+		this->src_seen = TRUE;
+		if (!this->src_matched)
+		{
+			hash = hash_payload->get_hash(hash_payload);
+			DBG3(DBG_IKE, "received src_hash %B", &hash);
+			if (chunk_equals(hash, src_hash))
+			{
+				this->src_matched = TRUE;
+			}
+		}
+	}
+	enumerator->destroy(enumerator);
+
+	chunk_free(&src_hash);
+	chunk_free(&dst_hash);
+
+	if (this->src_seen && this->dst_seen)
+	{
+		this->ike_sa->set_condition(this->ike_sa, COND_NAT_HERE,
+									!this->dst_matched);
+		this->ike_sa->set_condition(this->ike_sa, COND_NAT_THERE,
+									!this->src_matched);
+		config = this->ike_sa->get_ike_cfg(this->ike_sa);
+		if (this->dst_matched && this->src_matched &&
+			config->force_encap(config))
+		{
+			this->ike_sa->set_condition(this->ike_sa, COND_NAT_FAKE, TRUE);
+		}
+	}
+}
+
+METHOD(task_t, build_i, status_t,
+	private_ike_natd_v1_t *this, message_t *message)
+{
+	status_t result = NEED_MORE;
+
+	switch (message->get_exchange_type(message))
+	{
+		case AGGRESSIVE:
+		{	/* add NAT-D payloads to the second request, already processed
+			 * those by the responder contained in the first response */
+			result = SUCCESS;
+			/* fall */
+		}
+		case ID_PROT:
+		{	/* add NAT-D payloads to the second request, need to process
+			 * those by the responder contained in the second response */
+			if (message->get_payload(message, SECURITY_ASSOCIATION_V1))
+			{	/* wait for the second exchange */
+				return NEED_MORE;
+			}
+			add_natd_payloads(this, message);
+			return result;
+		}
+		default:
+			break;
+	}
+	return SUCCESS;
+}
+
+METHOD(task_t, process_i, status_t,
+	private_ike_natd_v1_t *this, message_t *message)
+{
+	status_t result = NEED_MORE;
+
+	if (!this->ike_sa->supports_extension(this->ike_sa, EXT_NATT))
+	{	/* we didn't receive VIDs inidcating support for NAT-T */
+		return SUCCESS;
+	}
+
+	switch (message->get_exchange_type(message))
+	{
+		case ID_PROT:
+		{	/* process NAT-D payloads in the second response, added them in the
+			 * second request already, so we're done afterwards */
+			if (message->get_payload(message, SECURITY_ASSOCIATION_V1))
+			{	/* wait for the second exchange */
+				return NEED_MORE;
+			}
+			result = SUCCESS;
+			/* fall */
+		}
+		case AGGRESSIVE:
+		{	/* process NAT-D payloads in the first response, add them in the
+			 * following second request */
+			process_payloads(this, message);
+
+			if (this->ike_sa->has_condition(this->ike_sa, COND_NAT_ANY))
+			{
+				this->ike_sa->float_ports(this->ike_sa);
+			}
+			return result;
+		}
+		default:
+			break;
+	}
+	return SUCCESS;
+}
+
+METHOD(task_t, process_r, status_t,
+	private_ike_natd_v1_t *this, message_t *message)
+{
+	status_t result = NEED_MORE;
+
+	if (!this->ike_sa->supports_extension(this->ike_sa, EXT_NATT))
+	{	/* we didn't receive VIDs indicating NAT-T support */
+		return SUCCESS;
+	}
+
+	switch (message->get_exchange_type(message))
+	{
+		case AGGRESSIVE:
+		{	/* proccess NAT-D payloads in the second request, already added ours
+			 * in the first response */
+			result = SUCCESS;
+			/* fall */
+		}
+		case ID_PROT:
+		{	/* process NAT-D payloads in the second request, need to add ours
+			 * to the second response */
+			if (message->get_payload(message, SECURITY_ASSOCIATION_V1))
+			{	/* wait for the second exchange */
+				return NEED_MORE;
+			}
+			process_payloads(this, message);
+			return result;
+		}
+		default:
+			break;
+	}
+	return SUCCESS;
+}
+
+METHOD(task_t, build_r, status_t,
+	private_ike_natd_v1_t *this, message_t *message)
+{
+	switch (message->get_exchange_type(message))
+	{
+		case ID_PROT:
+		{	/* add NAT-D payloads to second response, already processed those
+			 * contained in the second request */
+			if (message->get_payload(message, SECURITY_ASSOCIATION_V1))
+			{	/* wait for the second exchange */
+				return NEED_MORE;
+			}
+			add_natd_payloads(this, message);
+			return SUCCESS;
+		}
+		case AGGRESSIVE:
+		{	/* add NAT-D payloads to the first response, process those contained
+			 * in the following second request */
+			add_natd_payloads(this, message);
+			return NEED_MORE;
+		}
+		default:
+			break;
+	}
+	return SUCCESS;
+}
+
+METHOD(task_t, get_type, task_type_t,
+	private_ike_natd_v1_t *this)
+{
+	return TASK_IKE_NATD_V1;
+}
+
+METHOD(task_t, migrate, void,
+	private_ike_natd_v1_t *this, ike_sa_t *ike_sa)
+{
+	this->ike_sa = ike_sa;
+	this->src_seen = FALSE;
+	this->dst_seen = FALSE;
+	this->src_matched = FALSE;
+	this->dst_matched = FALSE;
+}
+
+METHOD(task_t, destroy, void,
+	private_ike_natd_v1_t *this)
+{
+	free(this);
+}
+
+/*
+ * Described in header.
+ */
+ike_natd_v1_t *ike_natd_v1_create(ike_sa_t *ike_sa, bool initiator)
+{
+	private_ike_natd_v1_t *this;
+
+	INIT(this,
+		.public = {
+			.task = {
+				.get_type = _get_type,
+				.migrate = _migrate,
+				.destroy = _destroy,
+			},
+		},
+		.ike_sa = ike_sa,
+		.keymat = (keymat_v1_t*)ike_sa->get_keymat(ike_sa),
+		.initiator = initiator,
+	);
+
+	if (initiator)
+	{
+		this->public.task.build = _build_i;
+		this->public.task.process = _process_i;
+	}
+	else
+	{
+		this->public.task.build = _build_r;
+		this->public.task.process = _process_r;
+	}
+
+	return &this->public;
+}

src/libcharon/sa/tasks/ike_natd_v1.h

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2011 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup ike_natd_v1 ike_natd_v1
+ * @{ @ingroup tasks
+ */
+
+#ifndef IKE_NATD_V1_H_
+#define IKE_NATD_V1_H_
+
+typedef struct ike_natd_v1_t ike_natd_v1_t;
+
+#include <library.h>
+#include <sa/ike_sa.h>
+#include <sa/tasks/task.h>
+
+/**
+ * Task of type ike_natd_v1, detects NAT situation in IKEv1 Phase 1.
+ */
+struct ike_natd_v1_t {
+
+	/**
+	 * Implements the task_t interface
+	 */
+	task_t task;
+};
+
+/**
+ * Create a new ike_natd_v1 task.
+ *
+ * @param ike_sa		IKE_SA this task works for
+ * @param initiator		TRUE if task is the original initiator
+ * @return				ike_natd_v1 task to handle by the task_manager
+ */
+ike_natd_v1_t *ike_natd_v1_create(ike_sa_t *ike_sa, bool initiator);
+
+#endif /** IKE_NATD_V1_H_ @}*/

src/libcharon/sa/tasks/task.c

@@ -38,6 +38,7 @@ ENUM(task_type_names, TASK_IKE_INIT, TASK_XAUTH_REQUEST,
 	"MAIN_MODE",
 	"QUICK_MODE",
 	"VENDOR_V1",
+	"IKE_NATD_V1",
 	"XAUTH_REQUEST",
 );
 #else
@@ -61,6 +62,7 @@ ENUM(task_type_names, TASK_IKE_INIT, TASK_XAUTH_REQUEST,
 	"MAIN_MODE",
 	"QUICK_MODE",
 	"VENDOR_V1",
+	"IKE_NATD_V1",
 	"XAUTH_REQUEST",
 );
 #endif /* ME */

src/libcharon/sa/tasks/task.h

@@ -75,6 +75,8 @@ enum task_type_t {
 	TASK_QUICK_MODE,
 	/** IKEv1 vendor ID payload handling */
 	TASK_VENDOR_V1,
+	/** IKEv1 NAT detection */
+	TASK_IKE_NATD_V1,
 	/** Request the user/pass with XAUTH */
 	TASK_XAUTH_REQUEST,
 };
@@ -122,7 +124,7 @@ struct task_t {
 	 *
 	 * @param message		message to read payloads from
 	 * @return
-	 * 						- FAILED if a critical error occurred
+	 *						- FAILED if a critical error occurred
 	 *						- DESTROY_ME if IKE_SA has been properly deleted
 	 *						- NEED_MORE if another call to build/process needed
 	 *						- SUCCESS if task completed